RH-PTB循环流量和混合特性的水模型研究

为深入了解RH-PTB真空精炼过程的循环流量及混合特性,建立了与RH装置原型的比例为1∶5.5的水模型,考察了不同工艺参数对RH-PTB循环流量及均混时间的影响.结果表明,随着气泡行程的增大、真空室内液面高度的增大及钢水处理量的减小,循环流量增大,均混时间缩短.因此在实际生产中,当钢水处理量过大时应采取措施增大循环流量.对实验数据进行回归处理得到了循环流量、均混时间的表达式.

Carbon and oxygen behavior in the RH degasser with carbon powder addition

For ultra-low-carbon(ULC)steel production,the higher oxygen content before Ruhrstahl-Heraeus(RH)decarburization(de-C)treatment could shorten the de-C time in the RH degasser.However,this would lead to oxidation rates being exceeded by molten steel production,affecting ULC steel surface quality.In this work,a carbon powder addition(CPA)process was proposed to reduce the dissolved oxygen content at the end of RH de-C through addition of carbon powder to molten steel in the vacuum vessel.Carbon and oxygen behavior during the CPA and conventional process was then studied.The results demonstrated that the de-C rate with CPA was lower compared to the conventional process,but the carbon content at the end of de-C presented no difference.The de-C reaction for CPA process took place in the four reaction sites:(1)within the bulk steel where the spontaneous CO bubbles form;(2)splashing area on the liquid steel surface;(3)Ar bubble surface;(4)molten steel surface.The CPA process could significantly reduce the dissolved oxygen content at the end of de-C,the sum content of FeO and MnO in the slag,the aluminum consumption,and the defect rate of rolled products.This was beneficial in improving ULC steel cleanliness.

Control of nonmetallic inclusions of non-oriented silicon steel sheets by the rare earth treatment

Based on the industrial production of non-oriented silicon steel, the rare earth （RE） treatment during the Ruhrstahl Heraeus （RH） refining process was studied. The morphology and the size distribution were observed for the steel specimens treated with different RE treatment conditions. Furthermore, the formation and change of the nonmetallic inclusion characteristics of finished steel sheets after the RE treatment were discussed. The results have shown that in the present work,the suitable RE metal additions are 0.6 -0.9 kg/t steel. After the suitable RE treatment,the formation of AIN and MnS inclusions were restrained, and the aggregation, flotation and removal of nonmetallic inclusions were efficiently promoted and the cleanliness of liquid steel was significantly increased. Meanwhile, the total oxygen concentration reached the minimum value and thle desulfurization efficiency was optimal ,and the type of main inclusions was approximately spherical or elliptical spherical RE radicle inclusions whose size was relatively large.

基于集成案例推理方法的RH精炼钢水终点温度预测

针对RH工序终点钢水温度预测问题,提出一种基于多元线性回归和遗传算法改进的集成案例推理方法.首先,针对一般案例推理方法中缺少影响因素精选方法的问题,利用多元线性回归进行属性约简;然后,针对案例检索中相似度计算缺少权重计算方法的问题,利用遗传算法进行权重优化;最后,基于精简的影响因素和优化的权重,利用改进灰色关联相似度进行案例检索,实现RH终点钢水温度预测.利用某钢铁企业RH工序实际生产数据分别对多元线性回归、BP神经网络、一般案例推理方法和集成案例推理方法进行测试,结果表明,集成案例推理方法在多个温度区间比多元线性回归、BP神经网络和一般案例推理方法都有更高的预测精度.

精炼炉设备技术改造

介绍了某钢厂通过对LF和RH精炼炉设备技术改造及优化,解决了LF精炼炉水冷炉盖冷却水控制和RH精炼炉真空系统水蒸气含水量大的问题,为生产高端钢材提供了稳定的设备保障。实践结果表明,这些措施对炼钢精炼过程中有显著的改善效果,并取得了可观的经济效益,对其他同类型的钢厂有实际的借鉴意义,具有很大的推广价值。

不同弓形浸渍管RH钢液流动行为的物理模拟

为提高真空循环脱气(RH)真空精炼的效率,设计了3种新型弓形浸渍管RH真空室,并建立了物理模型。通过水模拟实验研究了浸渍管形状、提升气体流量、浸渍管浸入钢液深度对弓形浸渍管RH和传统圆形浸渍管RH钢液循环流动的影响。结果表明,在实验气体流量范围内,3个弓形浸渍管RH比传统圆形浸渍管RH的循环流量增加了45%~218%,均混时间减少了15%以上。圆形浸渍管RH达最大吹气流量时,3种弓形浸渍管RH的循环流量仍线性增加。新型弓形浸渍管RH的最大提升气体流量可在传统圆形浸渍管RH提升气体流量(60?130 m^3/h)的基础上提高48%以上,方便短时间、高强度真空精炼操作。3种新型弓形浸渍管RH的循环流量随提升气体流量增加而线性增大,随浸渍管浸入钢液深度增加而增大,均混时间随提升气体流量和浸入深度增加而减小。现场应用时,弓形浸渍管其中2个面积较小的浸渍管浸入深度须大于545 mm,面积最大的浸入深度须大于818mm,3个弓形浸渍管RH的最大提升气体流量需控制在约173m^3/h。在现场现行的提升气体流量范围(60~130Nm^3/h)内,1#, 2#和3#弓形浸渍管RH的循环流量较传统圆形浸渍管RH分别约增加100%, 42%和112%,均混时间分别缩短30%, 15%和34%以上。在实验提升气体流量范围内,非对称弓形浸渍管RH的循环流量最大,均混时间最少。